The growth in energy consumption has outstripped the power generating capabilities in various areas. It is not uncommon in various regions for power utilities to mandate temporary reductions in power usage because of limited power generating capabilities. This is most prevalent in the summertime in conjunction with hot weather, when air conditioning usage peaks. Such air conditioning loads often represents the single largest power consumption loads for many residential and business locations.
In other instances, the power supply in the aggregate for a region is able to meet the power demand for the region, but limitations in the power distribution and transmission infrastructure result in instability, or unequal availability of power throughout the region. The blackout in the northeastern United States on Aug. 14, 2003 illustrates that impact of problems in power transmission and distribution can also lead to power outages and load imbalances.
If power consumption exceeds the available supply, regardless of insufficient power generation or inadequate distribution and transmission facilities, the power grid has automatic safeguards to limit the demand and prevent permanent damage to the power grid. These procedures may result in power blackouts and are undesirable as they indiscriminately remove power to all users located in a service area without warning. Another approach is to temporarily eliminate power on a planned basis to a selected service area. While still undesirable, this approach has the benefit of being planned and the impact (e.g., area effected) is known in advance. However, the economic costs of such blackouts is significant, and has been estimated by the government to cost the U.S. economy between $119-$188 billion dollars annually.
More preferable to rolling blackouts are approaches where power is maintained, but consumption is reduced so as to avoid a subsequent blackout. Typically, large power consumers (e.g., commercial and industrial customers) voluntarily enter into a demand load reduction program offered by the power utility. These arrangements are typically regulated by an appropriate state regulatory agency (e.g., Public Utility Commission) and in this arrangement customers agree to reduce or eliminate their load consumption upon request of the utility in exchange for a lower energy prices (power rates). Customers are typically requested to reduce their power consumption for a fixed number of hours (e.g., four hours) upon request, for a fixed number of times a year (e.g., six per year). If at the time of the request the customer does not reduce their power, then a penalty is levied on the customer. This requires the power utility to individually contact large energy consumers and request load reduction, which typically is accomplished by user deactivating a power load. Frequently, these users turn off or deactivate air conditioning systems or other industrial processes for a limited time period when usage is predicted to peak (e.g., typically afternoon). Often, peak usage is predictable and involves comparing past usage and anticipated temperatures. Thus, the need for limiting consumption can be often predicted hours in advance.
Typically, the power utility maintains a list of customers that consume large amounts of power, with names and telephone numbers for the purpose of requesting voluntary reduction in power usage. If a power reduction is required, utility personnel will telephone the customers and request power reduction. Under the incentive/disincentive program characteristics, customers typically comply as the alternative typically results in penalties and the ultimate result in a blackout.
The process of manually contacting and deactivating power loads is labor intensive and slow. Further, once a power utility contacts a customer for load reduction, the power utility has no immediate feedback as to whether the customer did reduce their power consumption and the associated impact. Typically, determination of a power load reduction is determined at the end of the billing cycle, and it is not clear whether the load was reduced for the entire time period or not. In addition, the power utility is not readily able to determine the real time power demand reduction by such power load demand activities, except at a very aggregate level. Consequently, the power utility may request far more (or less) power consumers to reduce their load than is required. Further, the power company is not able to tailor the time period for what is required. For example, the power utility may request load deactivation for a 4 hour window, but if after 3 hours it is determined that no further load reductions are required, the utility may not contact the various power consumers indicating that load reduction is not longer required. Contacting each of the power consumers may take so long so as to render the process moot.
Clearly, an automated approach for managing loads would be preferable. Further, the management of power loads may allow distinguishing between voluntary reduction and involuntary reduction. For example, if a power provider requires reducing power consumption, it may be preferable to obtain power reduction by voluntary load reduction, rather, than to institute involuntary power reduction. Typically, only if the voluntary reductions are insufficient are involuntary power reductions instituted. Thus, in managing loads, a user may require to know the distinction whether an indication for power reduction is a voluntary request or a precursor to a demand for power reduction.
Further, automated approaches may allow flexibility in defining load reduction programs. Users may selectively volunteer to reduce their power consumption if economic incentives are provided to them even, if they have not enlisted into a traditional power load reduction scheme. Thus, users not enlisted in a power load reduction scheme could still be offered an economic incentive via variable rate schedules for power consumption. A normal, or ‘off peak’ usage rate indicates the rate normally used to calculate a bill for power usage while a ‘peak rate’ indicates a higher rate for peak demand. However, communication of a dynamic schedule of peak/off peak rates can be scheduled on a real time basis to hundreds or thousands of users that would not be practical on a manual basis. Therefore, an automated approach for communicating rate schedules would be preferable.
Existing technology has not proven practical in many instances in addressing these problems, partly from a cost perspective. However, the wide scale development of a relatively recent developed wireless LAN standard known as IEEE 802.11 allows the low cost application of wireless technology to address many of the above problems, as well as providing additional benefits.
A major impediment to the application of wireless data communication technology is that in many circumstances, radio transmission is limited by regulation by the FCC. The FCC defines frequency bands, (‘spectrum’) which are subject to various regulations regarding its use and technical operation. For example, transmission of radio frequencies in most spectrum is regulated and only available for use by licensed entities. Thus, a power utility desiring to utilize wireless technology to remotely manage power loads would have to, in many cases, obtain a FCC license and comply with the associated regulations. In many instances, the regulatory compliance is complicated, and obtaining a license for using the spectrum can be very difficult and costly. Typically, a license requires a significant revenue producing application to justify its use.
The FCC has allocated a portion of the spectrum for unlicensed use, as defined in a portion of the regulations known as ‘Part 15’ of Title 47 of the Code of Federal Regulations. So-called ‘Part 15’ devices include garage door openers, cordless telephones, walkie-talkies, baby monitors, etc. These devices operate on defined channels in frequency bands and are subject to interference from other devices. To minimize interference, the FCC limits the maximum power that may be used during transmission.
A technology developed initially for the military radio communications, called ‘spread spectrum’ has been adapted for cellular applications and is now available for use in other applications at very economical costs. This technology has the benefit of minimizing interference from other devices using the same bandwidth. This technology is mandated by the FCC for equipment transmitting in a portion of the unlicensed spectrum, namely frequencies of 2.4 to 2.4835 GHz. The devices in this range typically are allowed to transmit at a maximum of 1 watt, though most transmit at a lower power. This technology allows a variety of users to share the spectrum and minimize interference with each other. Heretofore, the historical approach to minimizing such interference was to license the frequency to a specific entity, which in turn coordinates individual users (typically in the role of a service provider in relation to its subscribers).
The IEEE (Institute of Electrical and Electronics Engineers) sponsors various standards settings bodies, and the group known by the numerical designator “802” is responsible for various Local Area Network (LAN) standards. A group formed to define various wireless technical standards for LAN standards, is known as 802.11. This group has defined various approaches for using spread spectrum techniques in the unlicensed 2.4-2.4835 GHz spectrum for LANs and has spawned an entire industry of manufacturers building equipment allowing wireless data communication from various devices including laptops, PDAs, and other devices.
The 802.11 group has divided into various task groups focusing on various technologies and has evolved over time. The following lists some of the task groups and their focus:
802.11—Wireless LAN Physical and MAC layer specification (2.4 GHz.),
802.11a—Wireless LAN Physical and MAC layer specification (5 Ghz),
802.11b—Higher speed (5.5 and 11 Mbps),
802.11c—Bridge Operations,
802.11d—Operation in additional regulatory domains,
802.11e—Quality of Service parameters,
802.11f—Multi-vendor access point interoperability Access Distribution Systems,
802.11g—Higher rate (20 Mbps) extensions in the 2.4 GHz band,
802.11h—Enhancements for Dynamic Channel Selection,
802.11i—Security and Authentication.
Thus, the 802.11 suite of protocols encompasses a variety of past and present protocols designed to inter-work together.
The 802.11 protocols are based typically on using TCP/IP protocols, which are well known in the art and adapted from wireline LAN usage. This facilitates interworking of existing infrastructure (e.g., hardware and software) for use with the wireless LAN equipment. The wireless LAN task groups have defined various wireless architectures including end-points (also called stations) that originate and terminate information, and access points that provide access to a distribution infrastructure for extended communication. The 802.11 standard defines various capabilities and services associated with an end device pertinent to wireless operation. For example, 802.11 defines procedures to authenticate an end-point to an access point, associate/disassociated an end-point to an access point, ensure privacy and security, and transfer data between an 802.11 LAN and non-802.11 LAN.
The development of these standards along with industry cooperation to ensure interoperability has lead to equipment which when certified is termed “Wi-Fi” and can provide for wireless data communication heretofore not possible. The large-scale development of specialized semiconductors has lead to economies of scale allowing low cost equipment that heretofore has not been possible for wireless products. Thus, the use of 802.11-based equipment provides a whole new opportunity for communication capabilities for devices heretofore not possible. This allows greater automation and control for applications previously not considered.